Relief workers in Pakistan are scrambling to locate and reach survivors after Saturday's devastating earthquake. Rescue teams say landslides and rugged terrain have kept them from reaching parts of the most severely affected regions. With nearly 20,000 people killed, rescue workers say removing and burying the dead is another daunting task.

Sigurd Hanson, the country director for the U.S.-based aid agency, World Vision, says key access roads remain blocked by landslides. He says it is still not clear how soon aid workers will be able to reach many of the quake's victims and assess the extent of the damage in those areas.

Mr. Hanson says, in addition to shelter and medical supplies, many of the hardest hit areas need help tending the injured and burying the dead.

"Dead bodies are everywhere. Hospitals are completely full. Wounded are justlying around on the compound," Mr. Hanson says. "Unfortunately, when the earthquake initially hit,so many children are in school, so hundreds of school children died."

Pakistani officials have also acknowledged that the country was unprepared fora crisis of this magnitude, and desperately needs modern rescue equipment.

Even in the country's capital, Islamabad, where a 10-story building collapsedSaturday, a local rescue worker said there is enough manpower, but, withoutproper equipment, digging for survivors is slow and frustrating work.

"People cannot do much with their hands, and with not having the right kind ofequipment. That is the problem," the rescue worker says.

Two days after the building caved in, authorities say more than 50 survivorsmay remain beneath the mountain of broken cement.

Western countries are quickly stepping up to try and fill the gap. Severalteams with equipment have already come from countries offering aid, including the United States, Thailand, Japan and China.